The invention relates to a method and an apparatus for determining the geometry of a metallic workpiece in a forging press for a processing throughpass wherein the workpiece is fed into the forging press for processing and is rotated about the longitudinal axis in predetermined manner.
German Patent Specification No. DE 37 23825 A1 discloses a method for elongating a metallic workpiece in a forging press, wherein the workpiece, before the elongation concerned, or before the bite between the upper saddle and the lower saddle of the forging press, is in each case displaced in the direction of elongation of the workpiece only to such an extent--taking into account the elongation of the workpiece measured during the deformation--that the bite edge of the preceding bite, lies on the workpiece between the saddle edges. For measuring the elongation of the workpiece, an extensometer is connected with the workpiece by means of a measuring wire arranged detachably on the free end of the workpiece. This known method and apparatus have the disadvantage that only the elongation of a workpiece can be taken into account during processing with the aid of process control by a process computer, whereas the important alteration of cross section of a workpiece being processed is not taken into account in the process control.
Furthermore, conventional measuring methods are known, wherein the cross section of a workpiece at the supposed end of the processing operation is measured with measuring-tongs. Apart from the inexactitude of such a measuring process, this measuring process is unsuitable for process control of a processing operation and it is also unsuitable for workpieces which are difficult of access.
Furthermore, German Specification No. DE 34 14500 A1 describes a method and a device for measuring the profiles of irregular objects without contact, wherein the profile of the material is conveyed through an optical measuring path which rotates around the material which at least partially interrupts the light beam of the measuring path. The profile shape is determined by defining the interrupted light beam with the aid of suitable means. Thereby, it is true, it is possible to monitor the profile shape and also to adhere to required specifications, however an automatic processing operation is not controllable by this means.
Furthermore, there is known from German Specification No. DE 32 19389 A1 a contactless optoelectric measuring method, for determining non-round cross sections of elongate objects e.g. rolled and extruded profiles, wire etc, and an installation for operating the method, wherein a light beam, which undergoes a parallel displacement motion within a measurement field, is occluded by an object located in the measurement field, for a particular measurable time which is dependent upon the size of the cross section in the direction of scanning. When the orientation of the cross section of the object to be examined is non-variable with reference to the environment, the scanning takes place in several different directions, either by pivoting the entire measuring system about an axis which is parallel to the longitudinal axis of the object, or by collecting measurement values by means of several differently-aligned measuring systems, which then are formed stationarily. This known measuring method take non-round cross sections into account, but it is unsuitable for use during the control of a processing operation.
The object of the invention is to provide a method and apparatus for determining the geometry of a workpiece in a forging press, whereby the cross section of the workpiece is determined in simple manner and can be taken into account in the fully automated process control of a forging operation.